Crimping Unit for a Crimping Tool

ABSTRACT

A crimping unit is provided for a crimping tool for crimping workpieces. The unit includes a stand element for securing the crimping unit, a carrier element which is connected to the stand element in a linearly movable manner relative the stand element in a first movement direction, a slide element which is connected to the carrier element in a linearly movable manner relative to the carrier element in a second movement direction, and a crimping element which is designed to crimp the workpiece and is rigidly connected to the carrier element. The second movement direction is oriented substantially perpendicular to the first movement direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International Application No. PCT/EP2015/069114, filed Aug. 20, 2015, which claims priority under 35 U.S.C. §119 from German Patent Application No. 10 2014 218 280.8, filed Sep. 12, 2014, the entire disclosures of which are herein expressly incorporated by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a crimping unit for a crimping tool, to a crimping tool having a corresponding crimping unit, and to a method for retrofitting crimping tools with a corresponding crimping unit.

In the forming of workpieces made of sheet metal, use is made of crimping methods (often also referred to as “hemming methods”) in order to connect sheets made of the same or different materials together in a form-fitting manner by cold forming. In order, in particular, to produce body parts of motor vehicles, such as vehicle doors or other extensive sheet-metal body parts, for example, an outer sheet is connected inseparably to an inner structural sheet by crimping or hemming the sheet edges.

In the process referred to as “roll crimping”, the sheets are first of all preformed three-dimensionally with the aid of a deep-drawing method and trimmed. Subsequently, for example, the outer sheet is given a flange angled through about 90°. During the actual crimping operation, this flange is laid down fully on an edge of the structural sheet in several passes by a roll hemming tool guided along the flange by a robot. Usually, at least one tool change is necessary between the individual passes.

DE 692 00 577 T2 shows such a roll crimping method, in which an edge of a workpiece that consists of an outer plate with an upright peripheral edge and an inner plate is first of all bent at a defined angle by use of an edge bending roller. After this “precrimping” process, finish-crimping takes place with a different roller orientation or roller geometry, by way of which the angled sheet is finally bent over in a second rolling pass until the previously upright edge ultimately rests on a peripheral edge of the inner plate.

Although the roll crimping method is very flexible, the hem has to be traveled over several times along its entire length, considerably increasing the cycle time per component.

Also known are pressing tools having crimping jaws which crimp the sheets and connect them together in several pressing strokes. To this end, a flange of the sheet-metal parts to be connected is likewise first of all precrimped with a precrimping jaw before subsequently being finish-crimped with a finish-crimping jaw. The two steps can take place in two different pressing tools or with two different geometries of the crimping jaws. In any case, it is necessary to change the tool used.

WO 01/24954 A1 describes a hemming device in which use is made of only one hemming jaw and first of all a flange of the outer sheet is precrimped by a horizontal linear movement. Subsequently, the entire lower tool of the hemming device is raised, together with the hemming bed holding the sheet-metal parts, by a lifting movement and pressed against the hemming jaws in order to finish-crimp the already precrimped flange.

Such pressing tools require complicated hydraulics in order to raise the large and heavy lower tool and press it against the hemming jaw. The required hydraulic units are correspondingly complicated and the investment costs high. Control effort also proves to be very complex, since the heavy lower tool has to be moved against the hemming jaw as precisely as possible in order to achieve sufficient quality of the crimping.

On account of the complexity of the described installations, long planning and setup phases are conventional. A new acquisition or conversion for a new workpiece to be crimped at short notice is thus not possible.

Therefore, it is the object of the invention to provide a crimping tool that is as easy to produce as possible and allows a short cycle time with investment costs that are as low as possible. In addition, flexibility that is as great as possible for adaptation of the tool to new workpieces is intended to be achieved.

This object is achieved by a crimping unit, a crimping tool, a method for crimping and a method for retrofitting a crimping tool in accordance with embodiments of the invention.

Accordingly, a crimping unit for a crimping tool for crimping workpieces includes:

-   -   a stand element for fastening the crimping unit,     -   a carrier element which is connected to the stand element so as         to be movable linearly in a first direction of movement relative         to the stand element,     -   a slide element which is connected to the carrier element so as         to be movable linearly in a second direction of movement         relative to the carrier element, wherein the second direction of         movement is oriented substantially perpendicularly to the first         direction of movement, and     -   a crimping element which is configured to crimp the workpiece         and is connected rigidly to the slide element.

The stand element thus provides the fastening possibility for anchoring the entire crimping unit and to connect it for example to the crimping tool. The carrier element is connected to the stand element in a linearly movable manner and can thus be displaced in the first direction of movement with respect thereto. To this end, provision can be made for example of a first slide rail system between the stand element and the carrier element, said first slide rail system providing guidance of the movement in the first direction of movement and in an opposite direction thereto.

In the context of this description, movability in a first or second direction—unless described otherwise—should also always be understood as meaning the possibility of movement in the corresponding opposite direction, even if this is not explicitly mentioned each time.

The slide element is likewise designed so as to be linearly movable and, to this end, is correspondingly connected to the carrier element in a displaceable manner. For example, a second slide rail system can be provided between the slide element and the carrier element, said second slide rail system providing guidance of the movement in the second direction of movement and in an opposite direction thereto.

The crimping unit itself thus represents a module which autonomously allows a single crimping element to move in two directions in which it is possible for it to travel independently of one another. This affords the advantage that the crimping element can be used both for precrimping and for finish-crimping. Therefore, a tool change is not necessary and thus significantly shortens the cycle time. The modular and autonomous construction of the entire crimping unit furthermore makes it possible to configure it virtually independently of the crimping bed of the crimping tool. A complicated movement of the crimping bed is therefore not necessary. In addition, the modular construction affords the possibility of equipping existing crimping tools, for example roll crimping tools or pressing tools, with the crimping unit and thus of retrofitting them therewith in a particularly simple manner.

Preferably, the carrier element includes a corresponding geometry in order to arrange the first and second slide rail systems on the carrier element. For example, the carrier element has a substantially T-shaped or L-shaped geometry, wherein the slide rail systems are each fastened to one of the legs of the T-shaped or L-shaped geometry.

In each case, the first and the second direction of movement are oriented substantially perpendicularly to one another. In the context of this description, angles of between 70° and 110°, preferably between 80° and 100°, particularly preferably about 90°, are deemed to be substantially perpendicular.

The crimping unit connected to the slide element forms a tool which is brought into contact with the workpiece to be formed in order to deform the latter by crimping an edge region. Workpieces should be understood as being, in particular, sheet-metal workpieces made of aluminum sheet, steel sheet or sheets made of some other metal materials and combinations of different sheets.

The rigid connection of the crimping element to the slide element can take place in a force-fitting, form-fitting and/or materially integral manner, such that the crimping element can be moved together with the slide element. Preferably, the crimping element is connected to the slide element in a rigid but detachable manner, for example by a screw connection, such that, if required, the crimping element can be replaced or exchanged for a crimping element having an identical or different geometry. Alternatively, the crimping element can likewise be embodied in one piece with the slide element.

Furthermore, the crimping element can include:

-   -   a first crimping portion at least for precrimping the workpiece,         in particular a first crimping portion that is inclined or         curved with respect to the first direction of movement, and/or     -   a second crimping portion at least for finish-crimping the         workpiece.

This means that the crimping element has one or two crimping portions in order to precrimp and/or finish-crimp the workpiece. To this end, the respective portions can have a geometry that is as suitable as possible.

Thus, the first crimping portion that is able to be provided for precrimping can be configured in an inclined manner with respect to the first direction of movement. In other words, in the first crimping portion, the crimping element thus has a surface which is set at an angle with respect to the first direction of movement of the carrier element. Thus, as soon as the carrier element is displaced in the first direction of movement, the crimping element is also moved in the first direction of movement via the slide element and can deform the sheet to be crimped, or a flange of the sheet, by impinging thereon.

Alternatively, the first crimping portion can have a curved surface. Preferably, the curvature is embodied in a concave manner and thus defines a fillet. In this embodiment, too, the sheet, or the flange of the sheet, is deformed in an analogous manner as soon as the crimping portion is displaced against the flange and impinges thereon. A radius of curvature of the first crimping portion can accordingly be adapted to the flange to be formed.

Preferably, the sheet to be crimped is arranged such that a flange to be crimped is oriented substantially in the direction of the first direction of movement. In this case, the first crimping portion is angled in the same way with respect to the flange and can form the latter in a corresponding manner as soon as it is pressed against the flange.

The second crimping portion is configured in particular for finish-crimping. This means that its geometry impinges on the already precrimped flange when it is moved in the first direction of movement, such that the flange is formed fully. Therefore, the second crimping portion can be embodied substantially parallel to a subsequent orientation of the flange in the finish-crimped state.

The crimping element is suitable in particular for the production of what are referred to as “single crimps”, which can be embodied as “normal crimps”, “stepped crimps” or “hollow crimps”. The crimping element, and the first and/or second crimping portion thereof, can be geometrically shaped in a manner corresponding to the crimp to be produced. Thus, for example the surface of the second crimping portion can have a flat surface for producing a normal crimp or a corresponding step for stepped crimping of the flange.

According to one embodiment, the carrier element is movable in the first direction of movement at least between a first starting position and a first end position. Of course, any desired number of intermediate positions are likewise possible. It goes without saying that the respective positions and intermediate positions can be reached in any desired order and direction. The starting position should be understood as being a position in which the crimping element is spaced apart from the crimping bed, receiving the workpiece, of the crimping tool such that the workpiece can be inserted into the crimping bed.

According to a further embodiment, the slide element is movable in the second direction of movement at least between a second starting position, a precrimping position and/or a finish-crimping position. The possibly provided second slide rail system allows linear displacement in the second direction of movement between at least two of the three abovementioned positions. Of course, any desired number of intermediate positions are likewise possible. It goes without saying, here too, that the abovementioned positions and intermediate positions can be reached in any desired order and direction. The starting position should be understood as being a position in which the crimping element is spaced apart from a crimping bed, receiving the workpiece, of the crimping tool such that the workpiece can be inserted into the crimping bed.

Preferably, the carrier element and/or the slide element are each configured to be movable linearly by means of at least one pneumatically and/or hydraulically actuable drive, in particular a lifting cylinder, and/or an electromechanical drive. The drives allow, in particular, a sufficiently large drive force in order to provide the requisite force for crimping the workpieces. Moreover, these drives are especially suitable since they can maintain a respectively set position, even when the respective element is moved in the respectively other direction of movement. This is important in particular for the slide element, which is moved into the precrimping position or the finish-crimping position and is subsequently moved against the workpiece in the first direction of movement in order to crimp the flange.

Optionally, additional locking measures can be provided, in order to prevent unintentional displacement of the carrier element and/or of the slide element in that the particular element is able to be locked in at least one of said positions or intermediate positions.

The described drives, in particular the hydraulic drives, can be fastened directly to one or more elements of the crimping unit, for example to the slide element, the carrier element and/or the stand element.

According to a preferred exemplary embodiment, the carrier element is configured to be movable by a hydraulic drive and the slide element is configured to be movable by a pneumatic drive. Of course, the other described embodiments and combinations are also possible, however.

Furthermore, a crimping tool for crimping a workpiece includes:

-   -   a crimping bed for receiving the workpiece to be crimped, and     -   at least one crimping unit, wherein the crimping unit is         configured in accordance with the description.

In addition, the crimping tool can include at least one holding-down device for fixing the workpiece to the crimping bed. In this way, undesired displacement and detachment of the workpiece with respect to the crimping bed, in particular during precrimping and finish-crimping, can be prevented.

Furthermore, the stand element can be arranged in a fixed position with regard to the crimping bed. For example, it is possible to fasten the stand element to a common base plate of the crimping tool, the crimping bed also being connected to said base plate. Alternatively or in addition, the stand element can be fastened directly to the crimping bed. In particular, the crimping unit can be arranged directly at the peripheral surface of the crimping bed.

Furthermore, the crimping unit can be arranged such that the first direction of movement is oriented for a lifting movement or lowering movement of the carrier element relative to the crimping bed, and the second direction of movement is oriented for a linear movement of the crimping element in the direction of the crimping bed.

As has already been outlined, the first and second directions of movement always include the possibility of a movement in the respectively opposite direction.

According to a further preferred embodiment, the crimping tool can include a plurality of crimping units, wherein the crimping units are arranged adjacently to one another. This means that more than one crimping unit can be arranged next to one another in order to increase the width of the workpiece portion to be crimped. To this end, the crimping units can be configured identically. Preferably, the plurality of crimping units can partially or fully enclose the crimping bed and thus allow the workpiece to be processed at several points in succession or at the same time. The workpiece merely has to be inserted into the crimping tool once, and so, in this way, the cycle time can be considerably reduced again with respect to the known tools.

Furthermore, a method for crimping a workpiece with a crimping tool in accordance with the description is provided. The method includes the acts of:

-   -   inserting a first sheet, in particular an outer skin of a motor         vehicle component, into the crimping bed of the crimping tool,     -   arranging a second sheet, in particular a structural sheet, on         the first sheet,     -   precrimping a flange of the first sheet and/or second sheet with         the crimping element by way of a first linear movement of the         carrier element in the first direction of movement, and     -   finish-crimping the precrimped flange with the crimping element         by way of a second linear movement of the carrier element in the         first direction of movement.

In addition, according to one embodiment, the step of precrimping can first of all include a linear movement of the slide element in the second direction of movement for arranging the crimping element, in particular the first crimping portion, over the flange to be precrimped.

For example, the step of finish-crimping, following the precrimping, can first of all include a return movement of the carrier element counter to the movement of the carrier element in the first direction of movement for precrimping and/or a linear movement of the slide element in the second direction of movement from the precrimping position into a finish-crimping position for positioning the crimping element, in particular the second crimping portion, over the precrimped flange.

This means that the carrier element is first of all moved in the first direction of movement for precrimping. After precrimping, the carrier element is moved in the opposite direction to this previous movement. This occurs, however, before it is moved in the first direction of movement again, i.e. counter to the opposite direction, in a subsequent step for finish-crimping.

Furthermore, it is possible for the method, before the step of precrimping, to also include a step of fixing the first and/or second sheet with regard to the crimping bed, in particular by way of a holding-down device.

Of course, the method can additionally include one or more acts for applying an adhesive, in particular what is referred to as a lining adhesive, in order to adhesively bond at least the two sheets, in addition to bordering, with the aid of the adhesive and additionally to seal them off in that the adhesive can fill a resulting crimp joint. To this end, the adhesive can be applied to the first sheet and/or to the second sheet and be cured after the crimping operation has been completed.

Furthermore, a method for retrofitting a pressing and/or crimping tool with at least one crimping unit is presented, wherein the crimping unit is configured in accordance with the description and the tool comprises a crimping bed. The retrofitting method includes the acts of:

-   -   connecting the at least one crimping unit to the crimping tool         in that the stand element is fastened in a fixed position with         regard to the crimping bed.

In particular, with the described method for retrofitting, existing crimping installations can be extended to form a mixed configuration consisting of known crimping robots and crimping units according to the invention or the previous crimping robots can be replaced in their entirety.

For example, one or more crimping units can be added at defined locations in addition to existing crimping robots, or replace the latter, in order to allow easy, quick and secure crimping at least locally. In the exemplary case of a door panel to be crimped, this can be in particular a hem segment in the region of the window channel, which is accessible only with difficulty with the conventional crimping tools and usually requires a complicated tool change between the precrimping step and the hemming step.

Instead of this, the described retrofitting possibility allows the previous plant to be replaced and improved, such that the cycle time can be significantly reduced. As an additional aspect, an increased and reproducible quality of the crimping is achieved. The described crimping unit can be produced with comparatively low technical outlay and can be combined easily in a modular manner. It is accordingly possible to dispense with conventionally used roll hemming heads in these fields.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of a crimping unit according to the description.

FIG. 2 shows a first method step for crimping a workpiece with a second embodiment of a crimping unit according to the description.

FIG. 3 shows a second method step.

FIG. 4 shows a third method step.

FIG. 5 shows a fourth method step.

FIG. 6 shows a fifth method step.

FIG. 7 shows a sixth method step.

FIG. 8 shows a seventh method step.

FIG. 9 shows a schematic plan view of a third embodiment of a crimping tool according to the description.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a crimping unit 11 for a first embodiment, illustrated in parts, of a crimping tool 10 for crimping a workpiece W. The crimping unit 11 has a stand element 12 for fastening the crimping unit 11 and a carrier element 13 which is connected to the stand element 12 so as to be movable linearly in a first direction of movement A relative to the stand element 12. Furthermore, the crimping unit 11 has a slide element 14 which is connected to the carrier element 13 so as to be movable linearly in a second direction of movement B relative to the carrier element 13. In this case, the crimping unit 11 is configured such that the second direction of movement B is oriented substantially perpendicularly to the first direction of movement A.

Furthermore, a crimping element 15 is provided, which is configured to crimp the workpiece W and is connected rigidly to the slide element 14. To this end, the crimping element 15 has a first crimping portion 15 a which is inclined at an angle α1 to the first direction of movement A at least for precrimping the workpiece W.

Alternatively, the first crimping portion 15 a can be configured in a curved manner. A corresponding crimping element is illustrated in FIGS. 2 to 8 and can also be used for this first embodiment instead of the inclined first crimping portion 15 a.

Furthermore, the crimping element 15 has a second crimping portion 15 b which is provided at least to finish-crimp the workpiece W. This is arranged adjacently to the first crimping portion 15 a and is oriented perpendicularly (angle α2) to the first direction of movement A, and thus substantially parallel to the second direction of movement B, in the embodiment illustrated, and has a substantially flat surface for producing a “normal crimp”.

The carrier element 13 is movable at least between a first starting position and at least one further position, which are described in more detail in FIGS. 2 to 8, in the first direction of movement A. The same goes for the slide element 14, which is movable at least between a second starting position B′1, a precrimping position B′2 and a finish-crimping position B′3 in the second direction of movement B. The carrier element 13 and the slide element 14 can furthermore each be movable in desired intermediate positions between said positions.

For reasons of better clarity and presentability, the drives for the carrier element 13 and the slide element 14 are not illustrated. However, they can each be configured to be movable linearly by a pneumatically and/or hydraulically actuable drive, in particular a lifting cylinder, and/or an electromechanical drive.

The crimping unit 11 is part of the only partially illustrated crimping tool 10. The latter furthermore includes a crimping bed 19 for receiving the workpiece W to be crimped.

Optionally, the crimping tool 10 can include at least one holding-down device for fixing the workpiece W to the crimping bed 19, said holding-down device likewise not being illustrated.

It is possible to fasten the crimping unit 11 in a fixed position with regard to the crimping bed 19 by way of the stand element 12 in that the two are connected indirectly together by way of a merely indicated base plate 18. Alternatively, it is likewise possible to directly fasten the stand element 12 to the crimping bed 19 (this not being illustrated).

The crimping unit 11 is arranged such that the first direction of movement A is oriented for a lifting movement or lowering movement of the carrier element 13 relative to the crimping bed 19, and the second direction of movement B is oriented for a linear movement of the crimping element 15 in the direction of the crimping bed 19. In the embodiment illustrated, the first direction of movement A thus corresponds to a substantially vertical direction of movement and the second direction of movement B corresponds to a substantially horizontal direction of movement.

FIGS. 2 to 8 illustrate the method acts for crimping a workpiece W′ with an only partially illustrated crimping tool 20. In the illustrated second embodiment of the crimping tool 20, a crimping bed 29 and a crimping unit 21 are provided, the latter being optionally inclined slightly in the direction of the crimping bed 29 compared with the first embodiment illustrated in FIG. 1. The tilted arrangement affords the possibility of adapting the crimping element and the crimping direction to a possible inclined position of the workpiece or of the flange F′, such that the first direction of movement A′ is directed parallel to the orientation of the flange F′.

For the sake of clarity, of the crimping unit 21, only the carrier element 23 and the slide element 24 or the crimping element 25 are illustrated. Of course, the crimping unit 21 can nevertheless likewise include the components thereof that are not illustrated. In contrast to FIG. 1, the slide element 24 and the crimping element 25 are embodied in one piece with one another such that the two elements 24, 25 are designated together only as “slide element 24” in the following text. In addition, the crimping element 25 has a curved crimping portion 25 a.

It goes without saying that the described differing features of the second embodiment can likewise be used in any desired combination in the first embodiment. The same goes, conversely, for the use of the differing features of the first embodiment in the second embodiment.

The method for crimping the workpiece W′ comprises the step, illustrated in FIG. 2, of inserting the workpiece W′, which has a first sheet W′1, for example an outer skin, and a second sheet W′2. The two sheets W′1 and W′2 can be arranged in the crimping bed 29 of the crimping tool 20 together or in succession. The first sheet W′1 is already embodied with a flange F′ that is angled at about 90° to another surface of the sheet W′1. The carrier element 23 and the slide element 24 are each in their starting positions, which allow the insertion and arrangement of the first and second sheets W′1, W′2.

In FIG. 3, for the step of precrimping, first of all a linear movement of the slide element 24 in the second direction of movement B′ for arranging the crimping element 25, in particular the first crimping portion 25 a, over the flange F′ to be precrimped is illustrated. The movement thus extends from the starting position B′1 of the slide element 24 in the second direction of movement B′ as far as the precrimping position B′2 of the slide element 24, wherein the movement points in the direction of the crimping bed 29.

According to FIG. 4, the step of precrimping the flange F′ of the first sheet W′1 takes place with the aid of the crimping element 25, which is displaced in the first direction of movement A′ by a first linear movement of the carrier element 23. To this end, the carrier element 23 is lowered from the starting position A′1 into a precrimping position A′2, such that the flange F′ is impinged on by the curved first crimping portion 25 a and follows the surface geometry of the lowering first crimping portion 25 a. Accordingly, the flange F′ is bent over laterally.

The described sequence and orientation of the directions of movement A′, B′ has the particular advantage that the flange F′ is pressed against the crimping bed 29 by the linear movement of the carrier element 23. Lateral deviation of the sheets W′1, W′2 and associated folding of the sheets W′1, W′2 can thus especially be prevented.

In FIG. 5, for preparing the step of finish-crimping following precrimping, first of all a return movement of the carrier element 23 counter to the precrimping movement of the carrier element 23 in the first direction of movement A′ is provided. The carrier element 23 thus first of all carries out a lifting movement, which is directed counter to the lowering movement illustrated in FIG. 4.

Subsequently, a linear movement, illustrated in FIG. 6, of the slide element 24 in the second direction of movement B′ takes place out of the precrimping position B′2 into a finish-crimping position B′3 for positioning the crimping element 25, in particular the second crimping portion 25 b, above the precrimped flange F′.

The actual step of finish-crimping the precrimped flange F′ takes place according to FIG. 7 with the crimping element 25 by way of a second linear movement of the carrier element 23 in the first direction of movement A′. In this case, the carrier element 23 is lowered again in order to press the second crimping portion 25 b against the precrimped flange F′.

Subsequently, according to FIG. 8, the carrier element 23 and the slide element 24 are moved into the end positions A′1, B′1, illustrated previously in FIG. 2, again, in order to remove the crimped workpiece W′ and to be able to insert new sheets.

Optionally, prior to the step of precrimping, the method can furthermore include a step of fixing (not illustrated) the first and/or second sheet with regard to the crimping bed, in particular by way of a holding-down device (likewise not illustrated).

FIG. 9 shows a schematic plan view of a third embodiment of a crimping tool 90 in accordance with the description. Accordingly, the crimping tool 90 can include a plurality of crimping units 91 (for example two crimping units 91 are illustrated), wherein the crimping units 91 are arranged adjacently to one another in order to increase a width of the hem portion, to be crimped, of the workpiece W″. The crimping units 91 are preferably designed in an identical manner and enclose the crimping bed 99 only partially in the peripheral direction thereof (corresponds in this case to the plane of the drawing). Alternatively, however, several crimping units can also be provided, which entirely enclose the crimping bed. In any case, simultaneous processing of the workpiece W″ at several points in succession or at the same time is thus possible. The workpiece W″ in this case has to be inserted only a single time, such that, in this way, the cycle time can be reduced considerably compared with the known tools.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 

What is claimed is:
 1. A crimping unit for a crimping tool for crimping workpieces, comprising: a stand element for fastening the crimping unit; a carrier element which is connected to the stand element so as to be movable linearly in a first direction of movement relative to the stand element; a slide element which is connected to the carrier element so as to be movable linearly in a second direction of movement relative to the carrier element, wherein the second direction of movement is oriented substantially perpendicularly to the first direction of movement; and a crimping element which is configured to crimp the workpiece and is connected rigidly to the slide element.
 2. The crimping unit as claimed in claim 1, wherein the crimping element comprises: a first crimping portion at least for precrimping the workpiece, and/or a second crimping portion at least for finish-crimping the workpiece.
 3. The crimping unit as claimed in claim 2, wherein the first crimping portion is inclined or curved with respect to the first direction of movement.
 4. The crimping unit as claimed in claim 1, wherein the carrier element is movable in the first direction of movement at least between a first starting position and a first end position.
 5. The crimping unit as claimed in claim 4, wherein the slide element is movable in the second direction of movement at least between a second starting position, a precrimping position and/or a finish-crimping position.
 6. The crimping unit as claimed in claim 1, wherein the slide element is movable in the second direction of movement at least between a second starting position, a precrimping position and/or a finish-crimping position.
 7. The crimping unit as claimed in claim 1, where the carrier element and/or the slide element are each configured to be movable linearly by at least one pneumatically and/or hydraulically actuable drive.
 8. A crimping tool for crimping a workpiece, comprising: a crimping bed for receiving the workpiece to be crimped, and at least one crimping unit as claimed in claim
 1. 9. The crimping tool as claimed in claim 8, wherein the crimping tool comprises at least one holding-down device for fixing the workpiece to the crimping bed.
 10. The crimping tool as claimed in claim 8, wherein the stand element of the crimping unit is arranged in a fixed position with regard to the crimping bed.
 11. The crimping tool as claimed in claim 8, wherein the crimping unit is arranged such that the first direction of movement is oriented for a lifting movement or lowering movement of the carrier element relative to the crimping bed, and the second direction of movement is oriented for a linear movement of the crimping element in the direction of the crimping bed.
 12. The crimping tool as claimed in claim 8, wherein the crimping tool comprises a plurality of crimping units, and the crimping units are arranged adjacently to one another.
 13. A method for crimping a workpiece via a crimping tool having one or more crimping units, the method comprising the acts of: a. inserting a first sheet into a crimping bed of the crimping tool; b. arranging a second sheet on the first sheet; c. pre-crimping a flange of the first sheet and/or the second sheet via a crimping unit, the crimping unit comprising a stand element, a carrier element connected to the stand element so as to be movable linearly in a first direction of movement relative to the stand element, a slide element connected to the carrier element so as to be movable linearly in a second direction of movement relative to the carrier element, the second direction of movement being oriented substantially perpendicularly to the first direction of movement, and a crimping element connected rigidly to the slide element, wherein the pre-crimping of the flange is carried out with the crimping element by way of a first linear movement of the carrier element in the first direction of movement; and d. finish-crimping the pre-crimped flange with the crimping element of the crimping unit by way of a second linear movement of the carrier element in the first direction of movement.
 14. The method as claimed in claim 13, wherein the act of pre-crimping firstly comprises a linear movement of the slide element in the second direction of movement to arrange the crimping element over the flange to be pre-crimped.
 15. The method as claimed in claim 14, wherein the act of finish-crimping following the pre-crimping, firstly comprises a return movement of the carrier element counter to the movement of the carrier element in the first direction of movement, and/or a linear movement of the slide element in the second direction of movement from the pre-crimping position into a finish-crimping position for positioning the crimping element over the pre-crimped flange.
 16. The method as claimed in claim 15, wherein in the act of precrimping a first crimping portion of the crimping element is arranged over the flange to be precrimped, and in the act of finish-crimping, a second crimping portion of the crimping element is arranged over the precrimped flange.
 17. The method as claimed in claim 13, further comprising the act of: before precrimping the flange, fixing the first and/or second sheet with regard to the crimping bed via a holding-down device.
 18. A method of retrofitting a pressing and/or crimping tool having a crimping bed, the method comprising the acts of: providing one or more crimping units according to claim 1; and connecting the one or more crimping units to the crimping tool by fastening the stand element of the crimping unit in a fixed position with regard to the crimping bed of the crimping tool. 